Direct-acting engine.



G. H. GILMA.

DIRECT AGTING ENGINE. PBLLGMION FILED JULY e, 191 1.

Nw m6 QW G. H. GILMAN.

DIRECT ACTING ENGINE.

APPLICATION FILED JULY 6,1911.

1,058,668. v 4 Patented Apr. 8, 1913.

2 SHEETS-SHEET Z.

gm iis/@MMM as /s` 29 es La s y chmes.

TED FBTATE@ @ltblltll MAINE.

upon direct-acting engines, such, for eX ample, asare used with rock drilling mane object of the invention is to utilize an auxiliary reversing valve in connection rocated in opposite directions by projections fifi?) withI a tappet actuator and in such manner that the usual objections to a tappet actuator acting directly on Ythe mainvalve are overcome.

The present invention also overcomes those disadvantages which have resulted from prior attempts to actuate the main valve by pressure fluid controlled by a tap iet. I

l/lfhere a tappet actuator positively recipor shoulders on the piston is utilized to move directly the main controlling valve, the actuator must be relatively heavy and large and its .movement relatively great to impart the required .movement to the main controlling valve. The wear on such a form of actuator is considerable, resulting-in a gradual 'change inthe timing of the valve, while on the other hand it admits of little or no .range of, adjustn'ient in varying the length `oit oke the piston. it has been attempted to remedy these. defects by fitting the tappet itself with ports and utilizing it as a valve to reverse the main valve through. the pressure fluid control of the tappet. The abnormal wear on the tappet actuator, how-V ever, tends to wear its face and cause leakage impairing the actionof the valve. The chamber in which the tappet actuator Works, which chamber is usually opened to a grooved part of the piston, becomes filled with pressure fluid, tending to cause leakage to opposite ends of thel cylinder and ureventin the employment of such chamer for lu rication purposes;

pcclieatlon ol? Letters Patent.

Application llled July, 1911.

. illustration of DIRECMMQJUTENG' EN @3l-1N E.

Patented Apr. ti, MMS.. serial no. camco.

ln the present invention .a tappet actuator employed positively moved alternately in opposite directions by shoulders or other projections on the piston. This serves to actuate a separate reversing valve, which latten'preferably in the form of a slide valve, actuates the main controlling valve through the control of pressure iiuid. The auxiliary reversing valve may be placed in a separate chamber from the actuator and held in its seat by the pressure of the actuating fluid. It may be made very small and light and a very short stroke requiring therefore a small light tappet having but a slight movement and being subject to very little wear. This provides a condition where' 'through' the use of an auxiliary reversing valve, the length of piston stroke may bc adjusted within any required limits, the auxiliary valve is free from the disadvantages usually present in tappet actuated valves of this type.

Another object of the invention is the provision of an eliicient front head for t-he c Ilinder capable of withstanding wear and preventing leakage and at the saine time or' ready removal or renewal.

Another object of the invention is the provision of means for equalizing the strain upon the side rods of a roclr drill or other similar device.

The invention will .be best understood by reference to the following description when taken in connection with the accompanying one specific embodiment thereof, submitted for illustrative purposes only,p'while its scope will be more particularly pointed out in the appended claims.

In the drawings: Figure lis a plan view of a portion of a rock drill embodying one. form ofthe invention; Fig. .l`is a section in `plan of a modified form ol' 'front head; Fig.

2 is a sectional elevation on the line 2-2 in Fig. l showing the valve, valve chamber and ports in their relation to the cylinder; Fig. 3 is a section on an enlarged scale showing themain valve auxiliary valve and tappet actuator; Fig. 4 is auxiliary valve; Fig. 5 is a sectional plan taken on the line 5-5 in Fig. 3 showing the valve plate in plan; and Fig. 6 is a cross section in elevation on the line t-e in Referring to the drawings and to the embodinr i. of the invention there illustrated,

while Y a plan view of the 1 have shown the same embodied in e roel: drill, the cylinder whereof is shown at 1, the piston et 2, and the mein vulve chest et 3. The compressed oir or other pressure fluid which be employed enters the valve chest 3 (from a sourceof supply not shown) through an appropriate supply inlet 4 and is controlled in its passage to the opposite ends of the cylinder 1 by the moin controlling valve 5.

Referring to 3, the mein controlling; valve may be of any suitable type, but. here in comprises three spools 5, und 8 et aquel diameter connected portions reduced diameter, the control spool 7 controlling' communica-tion Ween asupply port und cylinder ports respectively 10 and 11. The port 10 is connected to the passage 12 leed.- ing to the tool end of the cylinder and the port'll to the passage 13, leading to the heed end of the cylinderl rlhe spool 5 controls communication between the cylinder port l0 and an exhaust port 14 end the spool 8 iitrole communication between the cylinder port 11 and on exhaust port 15. in one position' of the vulve, therefore, (the position shown in Fig. 3) the admission port 9 is connected to the rear end of thc cylinder through the port 11 and passage 13, the piston under such conditions being propelled forward in' the direction or the arrow shown in Fig. 3. End buffers 16 and 17 are provided and on the movement of the velveto the opposite position with the spool 8 against the buffer 17 reverse conditions pertain, that is to soy, pressure i'luid is exhausted :through the passage 12 and port 10 from the forward end of the cylinder und pressure liuid admitted through the port 11 and passage 13 to theftool or forward 'end of the cylinder.

To reverse the nein vulve 5, auxiliary valve is employed, herein in the form of tiet slide valve 18, the letter in turn being given a'short quick movement et en appropriate time by the teppet actuator 19 which Visedapted to engage appropriately shaped inclined beveled shoulders 2C' and 21 constituting teppet surfaces on the piston 2.

Preferably, es shown, the valve actuator is in the form of :t sliding segment having an upwardly' projecting tooth 22 entering the under tace of the slide volvo 1.8, the tooth end its recess in the slide valve being preferably shztpedto give appropriate roll ing contact between the engaging surncos and thereby reduce the weer on the valve to u minimum.

The segment 19 slides in suitable urcshaped guider/*aye herein formed in the Walls of the 'valve plete Q3, the valve plate being clamped between the air chest and the cylinder and movidu]g3r e seat t'or the slide valve 18 which therefore works in ay chumber between/,the air chest andI the valve :weones removing the vulve chest the with the slide Vvulve und actu :is e, unit.

To control the incin vulve through the i ely, the letter coing in 'tree f.:ouxu1uni c: ion with the rcsi'iective ports lil und l5' uith un exhaust ou (let e( the .side oi' the cylinder und below the vulve pluie (not sh own) Pressure fluid is supplied directly toull. parts of the auxiliary vulve chamber from the admission port 9 through the pussoge und the grooves und 3G so that 'the slide sont by pressure, The vulve plete has ucent the ports 26 und 27 grooves or po: 3T und 38, respectively, end the vulve has opposed Coperetiug grooves or ports 3f) und d0. l

llhen the the velve'h'us been moved to the position shown in Fig. 3,' by the beelt- Wzu'd movement of the piston, the port 27 is opened to the actuating iuid through the ports 40 and und the port 26 to the exhaust through the port 39 so that pressure :duid admitted against thel end spool. 8 und exhausted from the opposite end of the mein controllirvalve throwing the vulve to the position s iown. As the piston moves ent )un be removed from ille cylroo torwardin the direction of theerrow 3) the shoulder 21 will engage the end of the tappet actuator und move the lutter in its guideways und throw the slide vulve forward, opening the port 2G to the pressure fluid supply and the port :27 to the exhaust, thereby throwing the moin controlling vulve to its opposite position and reversing the pressure conditions in the cylinder.

Since the tnppet actuator wor-lis in u chamber Separate from the :iux'ilieiy vulve chamber, the space surrounding the reduced portion ot the piston between the shoulders 2O und 21 nieybelnede u dead oir space und utilized :is a lubricating chamber, thus ,not only increasing the ciiioicncy ot the cnuinc but preventing leakage from one endof the cylinder to the' other, The striking Vof the piston against the nctuntor docs not tend *oo lit't the vulve from its sont or otherwiseimpair the fiction of 'the valve, and the slight weer which the .slide vulve undergoes docs not in any wey atleet its action. iVhen this form ot vulve is used on :L roclt drill, by adjusting the feed screw ot the drill. the stroke of the piston may be adjusted from e very short strolge accompanied by u more flutter of the valve to the full piston stroke.

` egeinst 'the piston rod di. diameter 'of the gland geo - eveled so that they tend to com it the usuel feed-screw is turned so as to a-lvente the cylinder toward the work, a point will finally be reached where the tool will be arrested by striking the stone in such a position as to bring the rear edge of the inoline 2l just under 'they rear end of thesegmental ectuotor 1.9. The letter is moved, and the valve reversed, just about the time when the tool strikes the work, and the piston is immediately arrested by the impact, and its rearward movement begun. On this rearward movement, however, the piston has only to move e little more than the ineline 21, when the forward end of the actuator encounters the incline 20, and is moved in the opposite direction. By this ineens, the stroke con be restricted, so that the velve 'reverses on a very slip-nt movenient of the piston. By altering the position of' the two tappeti shoulders or surfaces 2O and 21 the length of piston stroke may be increased to any required length or reduced to any amount above the liinit required for the movement of the valve itself. The teppet and the 'valve can both be made very light Vand the tappet movement less thunholf ot that required when the mein controlling vulve is actuated directly Referring now to the construction of the rock drill cylinder, the piston 2 (Figs. l and 2l is connected which latter is adapted to curry :it its outer end a chuck (not shown) for receiving the drill. The front end ot the cylinder is closed by e heed of improved constructionv through which the piston rod passes. Reerring toFigs. l and 2, the front head comprises e ringr heed 42, the upper end of which is {misto-conical and is counterbored to tit accurately the outside of the cylinder. The forward end of the cylinder erebly turned on centric with the overlapping' end within the cone steeped end of the ring head is a, split bushing;d 4&3 which letter has a projection LA of reduced diameter entering a counterhored portion of the' cylinder. The forward end ot the .ri-ng head is pertielly split and internally the outside to make it con; bore and to receive the The opu'shing ere Dress packsplit bushing with stud jointsi isv spiined bet veen them posing ends of the gland and ing 46 which isslightly greater than the piston so that-the letteren-n be passed through the ring,- head. The head con he packed by merely removing the gland and without untestening the side rods of the drill. Bot-h the bushing and the gland ere bored accurately to fit the piston rod sind by meen-s of the internal projection 44 on the bushing and the external to the piston rod llf is pref-v ot the ring head. Seated threaded and is ,provided with e. gland 45 in the form of a' he outside y leakage 'by providing en accurate metallic joint between the heed and the cylinder.

The leakage furthermore is not only pre.

vented bythe overlapping shoulder on the ring heed andthe bushing, but also by a slight clearance 48 which-is left between the bushin and the ring heed. Any pressure Huid uiich leuks from the forward end of the cylinder tends to condense in this space and to form a. water seal rendering leakage still more unlikely. The ring head as shown in Fig. l is provided with side Wings 49 whichare perforated to receive the side rods 50, the latter being,- fastened in the front head by the nuts 51 and the intervening springs a In Fig. 1u l have shown uy slightly modified form of the front head, the walls of the ring head being tapered for their full length and there being provided ya, single bushing and a. packing 54 placed in a groove in said bushing. This form of front heed, however, is also provided with similar internal und external dowel projections to those shown in Fig. 2.

At their rear ends the side rods poss through lugs 55 on the cylinder serving to clump the bottom head and top head 56 together. I have found that much breakage which occurs through the shock imparted to the side rods b the piston strikinv thebottom head can lie avoided b equalizing the shock upon the two rods. or this purpose I have connected the side rods by an equalizing,r device herein consisting of an equalizing yoke bei" 57 to the ends of which the side rods ere bolted. The yoke ber has 2i curved inner face which rests against a pret-- erably Het seat provided in the end of the top heed between the lugs 58 so that it can rock slightly thereon and tend to equalize the'uequel strains to which the side rods may be `'subjected without in `any way iinpairing their eiliciencvin clamping the cyl- ,luder and heads together.

While I have herein'shown and described :toipurposes of illustration one form of the invention, it is to be understood that-the same is not limited, to the details of con-l struction or the form or ment of parte or to ,the specific application of the invention, but that extensive deviations may be made therefrom without departing from the spirit of the invention.

l. The combination with acylinder of a. p iston provided intermediate its ends With relative arrangesmgle teppet means, o tappet controlled lin opposite directions,

"throughout its sfil'oka positive @Onflc of adapted o be mow/*eri positively 1n opposlte dlrectlns by sald appes, a

arate auxiliary valve moved the acwtor :mda main condoling valve 'evesed 3j; 'the pressux'e ud conro-Q by valve.'

3, The combnaon 73: Ii .1 a 'jflef ou' :f1 pxston prou-'med with tap# ppi conmled valve :1c-tu be ,1 adapibef to be engaged by 13h-e math anti moved thereby, and a main conzmln valve.

. reversed by pessme fluid conwled by he :L Xiliary valve.

4. 'In an engine, 'the cylinder, of a, valve actuator piston hi.

ing Within Said cy'nde at all times W'h :m mainta" control 0f said lacuio im mo ternately in opnos controlling valve rever 4 l controlled by sam auxlhm'y ".Yaijve.

5. En an engie5 Combination vv' cyhnder, of a Valve acuatmg a plsslan 5pyeratmg Wlth u52 actuaoy and mam said actuator 'to move H3@ same altemately an mfxizuf] valve. moved my said acuuaof; and mam contQL 'ling valve reversed by pre? r fini@ com trolled 'by said auxinx'y vm G. The combination *wi L Walls for a tappa" ato' movable in A ed to be moved by 'i auxlay Valve W01; L formed 'by said piana an: tween the air chest 2115i actuai'ed'by said appe Combirwiion Riku piston provided 'th 1 zijn axillary' valve, zweq by said n and a mam conl'rmmg 'm coniz'mlea n).

tanppet-conmled valve-mhh :m er 5min Valve resepa-m ed :from

ma, the space um in? the plsr ai; iw@ opposite points movm w1 1d. a. @tuant-o1' Said auxiliary engine, the cambinfxim with nv W uctunwr -fL pvlon hav 

